Dnsmasq has changed the way it works in 12.10 - can someone point me to documentation or info on the changes

Solution 1:

NetworkManager talks with dnsmasq over dbus now. This has one advantage: dnsmasq does not have to be restartet everytime something changes.

The big downside: You can't really see what's going on anymore. /var/log/syslog now has entries that describe what goes on a bit:

Jan 21 22:10:13 bogo dnsmasq[28993]: vorgelagerte Server von DBus gesetzt
Jan 21 22:10:13 bogo dnsmasq[28993]: Benutze Namensserver 192.168.3.3#53

But that's - in my eyes - not really a satisfying solution, especially when something goes wrong.

Solution 2:

There is mention of one of the changes in the Networking stanza of the Quantal release notes.

https://wiki.ubuntu.com/QuantalQuetzal/ReleaseNotes/UbuntuDesktop

The information that was formerly in /var/run/nm-dns-dnsmasq.conf is no longer in a file, but you can extract information using nmcli or nm-tool as has been described in other answers such as

How to know what DNS am I using in Ubuntu 12.04